private List<RaycastHitResult> RaycastAllInternal(Ray ray)
{
if (Map == null)
throw new InvalidOperationException("Cannot raycast against an unloaded map!");
List<RaycastHitResult> returnResults = new List<RaycastHitResult>();
foreach (Room room in Map.Rooms)
{
foreach (var entity in room.Entities)
{
if (!Map.LayerIsVisible(entity.Layer))
continue;
SceneComponent sceneEntity = entity as SceneComponent;
if (sceneEntity == null)
continue;
Vector3 aabbMin, aabbMax;
sceneEntity.GetAABB(out aabbMin, out aabbMax);
float intersectionDist;
if (RayIntersectsAABB(ray, aabbMin, aabbMax, out intersectionDist))
{
RaycastHitResult result = new RaycastHitResult();
result.Distance = intersectionDist;
result.Entity = entity;
returnResults.Add(result);
}
}
}
// Sort the results - nearest to furthest.
returnResults = returnResults.OrderBy(x => x.Distance).ToList();
return returnResults;
}
/// <summary>
/// Returns all results (sorted in closest to furthest) order which intersect the <see cref="Ray"/>, or an
/// empty list if there are no results.
/// </summary>
/// <param name="ray"></param>
/// <returns></returns>
public List<MapEntity> RaycastAll(Ray ray)
{
var allResults = RaycastAllInternal(ray);
List<MapEntity> outputList = new List<MapEntity>();
foreach (var result in allResults)
outputList.Add(result.Entity);
return outputList;
}
private static bool RayIntersectsAABB(Ray ray, Vector3 aabbMin, Vector3 aabbMax, out float intersectionDistance)
{
Vector3 t_1 = new Vector3(), t_2 = new Vector3();
float tNear = float.MinValue;
float tFar = float.MaxValue;
// Test infinite planes in each directin.
for (int i = 0; i < 3; i++)
{
// Ray is parallel to planes in this direction.
if (ray.Direction[i] == 0)
{
if ((ray.Origin[i] < aabbMin[i]) || (ray.Origin[i] > aabbMax[i]))
{
// Parallel and outside of the box, thus no intersection is possible.
intersectionDistance = float.MinValue;
return false;
}
}
else
{
t_1[i] = (aabbMin[i] - ray.Origin[i]) / ray.Direction[i];
t_2[i] = (aabbMax[i] - ray.Origin[i]) / ray.Direction[i];
// Ensure T_1 holds values for intersection with near plane.
if (t_1[i] > t_2[i])
{
Vector3 temp = t_2;
t_2 = t_1;
t_1 = temp;
}
if (t_1[i] > tNear)
tNear = t_1[i];
if (t_2[i] < tFar)
tFar = t_2[i];
if ((tNear > tFar) || (tFar < 0))
{
intersectionDistance = float.MinValue;
return false;
}
}
}
intersectionDistance = tNear;
return true;
}
/// <summary>
/// Returns the closest result which intersects the Ray, or null if there is nothing.
/// </summary>
/// <param name="ray">Ray along which to check for intersections.</param>
/// <returns>Closest MapEntity, or null if none.</returns>
public MapEntity Raycast(Ray ray)
{
var allEnts = RaycastAllInternal(ray);
if (allEnts.Count > 0)
return allEnts[0].Entity;
return null;
}
